I'd say it's more a hindmilk thing than anything, both my kids would change there poo colour frequently (both Breastfed) so we never knew what we were gonna get when we took off the nappy
if she is otherwise content I wouldn't worry to much try to take note of how long she feeds for Hailey was a grazer so she would have short frequent feeds, causing her poos to change constsantly, Ben was a not so frequent feeder but would feed for much much longer then Hailey so while his poos would change colour they wouldn't change as often as Hailey's did....gosh i hope that made sense